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Survey of Nebraska and Wisconsin soybean producers on dicamba use during 2017 and 2018

Maxwel C. Oliveira1, Christopher Proctor2, Paul Mitchell1, Amit Jhala2 and Rodrigo Werle1

1 University of Wisconsin-Madison and 2 University of Nebraska-Lincoln

1Corresponding author’s E-mail: max.oliveira@wisc.edu

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INTRODUCTION

  • Due to off-target dicamba movement incidents during the 2017 and 2018 growing seasons, adoption of the Xtend technology (dicamba and glyphosate-tolerant soybeans) has become a controversial topic in the United States.

  • The OBJECTIVE of the survey was to understand Nebraska and Wisconsin stakeholders’ adoption and opinion related to the Xtend technology.

MATERIAL AND METHODS

Survey
  • From August through September of 2018, a survey containing 22 questions related to soybean, dicamba and weed management was conducted in Nebraska and Wisconsin (Figure 1).
Figure 1. Survey questions of soybean production and dicamba use in Nebraska and Wisconsin.

Figure 1. Survey questions of soybean production and dicamba use in Nebraska and Wisconsin.

Data analysis
  • Survey respondents as agronomist, co-op, university and industry representatives were grouped into Decision influencer.

  • Data are presented as a % of responses from decision influencer and farmer of Nebraska and Wisconsin.

  • Q4 is presented as the share of Xtend hectares compared to the total of soybean hactares reported in Q3; Q5 is the share of PRE-applied dicamba hectares compared to the total of Xtend hactares reported in Q4; Q6 is the share of POST-applied dicamba hectares compared to the total of Xtend hactares reported in Q4.

  • Data analysis was conducted in R statistical software using functions %>%, select, summarise, group, filter and mutate of tidyverse (ggplot, tidyr, dplyr) package.

  • Method loess (local polynomial) regression fitting was performed in Q4, Q5, and Q6 (Figures 4, 5, and 6).

RESULTS

Figure 2. Map of survey respondents of Nebraska and Wisconsin.

Figure 2. Map of survey respondents of Nebraska and Wisconsin.

Figure 3. Primary role of survey respontens from Nebraska (n=316) and Wisconsin (n=149).

Figure 3. Primary role of survey respontens from Nebraska (n=316) and Wisconsin (n=149).

Figure 4. Share of Xtend soybean hectares planted in Nebraska and Wisconsin.

Figure 4. Share of Xtend soybean hectares planted in Nebraska and Wisconsin.

Figure 5. Share of PRE-applied dicamba in Xtend soybean hectares in Nebraska and Wisconsin.

Figure 5. Share of PRE-applied dicamba in Xtend soybean hectares in Nebraska and Wisconsin.

Figure 6. Share of POST-applied dicamba in Xtend soybean hectares in Nebraska and Wisconsin.

Figure 6. Share of POST-applied dicamba in Xtend soybean hectares in Nebraska and Wisconsin.

RESULTS

Figure 7. General farm management.

Figure 7. General farm management.

Figure 8. Dicamba formulation adopted in Nebraska (n=149) and Wiscosnin (n=44).

Figure 8. Dicamba formulation adopted in Nebraska (n=149) and Wiscosnin (n=44).

Dicamba application POST-emergence in Xtend soybean
Figure 9. Dicamba application POST-emergence in Xtend soybeans.

Figure 9. Dicamba application POST-emergence in Xtend soybeans.

Non-Xtend soybean hectares
Figure 10. Impact on non-Xtend soybeans hectares.

Figure 10. Impact on non-Xtend soybeans hectares.

Figure 11. Main causes for dicamba injury according to survey respondents to non-Xtend soybeans

Figure 11. Main causes for dicamba injury according to survey respondents to non-Xtend soybeans